Mention of schools here-it goes along with what was said today that several measures used together and well timed can work better than different strategies used in sequence reaction to events. Someone upthread mentioned the holy cheese analogy where the holes in each slice are covered by different holes in others, thus slowing spread. I'm not an expert at all, but I think it sounds like some sort of synergy. I was just interested to try to find the research base they are using. I've only done a quick google but this seems to be a meta analysis of several studies.
'Four strands of evidence emerged from the outbreak reports. First, they provided further evidence linking mass gatherings with influenza transmission. Second, the evidence suggests that crowd density and event duration may be the key characteristics of a mass gathering that determine the risk of influenza transmission. There is some new evidence that ships provide an example of a specialised setting that may be a risk factor for influenza outbreaks, particularly out of season. It is therefore argued that the mass gathering definition should be expanded to include civilian and military ships. Third, some evidence suggests that mass gatherings can be “seeding” events leading to the introduction of new strains of influenza into the host geographical area, or instigating community transmission in the early stages of a pandemic. Finally, evidence from the historical outbreak analyses suggests that, when implemented in combination with other social distancing interventions such as isolation measures and school closures, restriction of mass gatherings may significantly help to reduce influenza transmission. It was not possible to tease out from the data available any conclusive evidence on the individual effect of restriction of mass gatherings. However there was no new evidence to support hypotheses that restrictions can be effective at reducing influenza transmission in these settings'